Cascade setup & looping simulation

[Alexx31]

Hello,

I have a river setup, where I am testing a cascade setup now.

- is it correct, that I just have to duplicate the simulator and "reset the output to default" and can already use it as a cascade?
I will need it only for rendering.
And I would have to start the simulation from the second (later) simulator, in order to get both working)

- for compositing: would it be possible to render each simulator without the other? (to assemble them only later)

- looping simulation: Is that also with a cascade setup possible?

- I read now also, that it does not speed up the workflow with liquids? (if not which sense has it then?)

Thanks

[Svetlin.Nikolov]

Hey,

Not sure where you read that cascade will not speed up the workflow, can you please share the link? It will not speed up one simulation, but if you have a series of Simulators, such as Sim1 -> Sim2 -> Sim3 and you only want to adjust the final Sim3, with a Cascade setup you don't need to simulate the entire river, but instead you can only simulate the final segment that Sim3 covers - this will definitely speed up your workflow. Here is more information on cascade simulations: https://docs.chaos.com/display/PHX4M...een+Simulators

Looping is a render-time effect, so once you are happy with all simulations, you could enable it as long as it looks good. Remember that it is up to you to pick such an interval in the simulation that looks good when you loop it - such that the end frame looks very much like the starting frame. With a river or waterfall simulation, you have to wait for the river to fully fill up with water and just then pick the starting frame for the loop. Here you can find more info on the looping parameters and Time Bend controls in general: https://docs.chaos.com/display/PHX4MAX/Liquid+Input

When you don't want to render a Phoenix Simulator (which provides the mesh in a river simulation) or Particle Shader (which renders the bubbles and the splashes), you can just make it not-renderable from its right click Properties. If you want to get passes for the different simulators and particles, you must switch the Particle Shaders to Render as Geometry: https://docs.chaos.com/display/PHX4M...ements+Support

Duplicating the simulator and resetting the output sounds right - it's best to use the exact same Dynamics settings between all cascade simulators

"And I would have to start the simulation from the second (later) simulator, in order to get both working)" -> This makes me think I need to explain cascade simulations more: You run Sim1, then it finished and you run Sim2 - the liquid flows from Sim1 into Sim2. If you are not happy with how Sim1 looks, you need to run Sim1 and then Sim2 again. But if you want to adjust only the lower part of the liquid, you could just iterate on Sim2 without touching Sim1. Please also check the first link above and if you still have questions, ping me.

Hope this helps, cheers!

[Alexx31]

- The idea is to have a situation like a waterfall, it should never stop in the first simulator to pour new liquid, I want the complete flow simulating all the time.
So it makes here no sense to use a cascade?

- Can I maybe loop the first simulator and use this as input for the second simulator?

(p.s. I made now a test with one cascade, it stopped for no reason after 20 frames completely with pouring liquid in the first (start) simulator.. I have to examine, but I'm mentioning in case there is something obvious I might have missed).

[Svetlin.Nikolov]

Oh, just the opposite - it makes perfect sense to use a cascade for this setup. Waterfalls are one of the best fits for a cascade simulation. The top sim keeps emitting, the water flows into the bottom sim all the time.

As for the stopped simulation, was there any error message? If not, is it possible that you accidentally hit the ESC key? You can make sure this won't be a problem by disabling thia key from the Phoenix FD menu -> Global Preferences.

Cheers!

[Alexx31]

Hi Svetlin,
would it be possible to connect different simulations in a loop with blending?
Example: I have 400 frames of four different simulations (each has 100 frames) and I want to blend from one to another within 20 frames.

The reason is, that in one specific water simulation a special part in the beginning is interesting, which doesn't occur later again in that way.
But only looping the same two seconds would be to obviously a loop.
I could simulate the beginning with slightly different settings, to achieve that it is not looking looping.

I thought maybe when I could animate the "cache origin", that the start changes, while the sequence is not in the blending state.
And then I could through all simulations into the same folder, just with different "start" numbers.

Thanks

[Svetlin.Nikolov]

Ah, sorry for the late reply! It's not possible to blend frames from different simulators right now and it might not look very well even if it was allowed to do that because of different shapes of emitters, etc..